This question has been asked and answered here, but I can't find an example that makes sense to me. I am testing some code and trying to create an object in main from a class I made called Cube that inherits from a class called Solids that inherits from an abstract class called Shapes (I have to do it this way). My question is what can I do to fix the "AbstractShape.this cannot be referenced from a static context" error I am getting regarding my creation of cube1. Sorry if this is remedial, I am learning at the moment

这个问题已经在这里被问到和回答了，但我找不到一个对我有意义的例子。我正在测试一些代码，并试图在Main中从我创建的一个名为Cube的类中创建一个对象，该对象继承自一个名为Solids的类，而这个类继承自一个名为Shape的抽象类(我必须这样做)。我的问题是，我可以做些什么来修复我在创建cube1时遇到的“AbstractShape.This Cannot be Reference from a Static Context”错误。抱歉，如果这是补救措施，我现在正在学习

public class AbstractShape {
    public static void main(String[] args)throws Exception{
        Cube cube1 = new Cube(4,4,4);
        cube1.calcArea();
        cube1.print();
        Solids [] MySolids = new Solids[2];


    }
    abstract class Shapes{
        public abstract double getArea();
        public abstract double getVolume();
        public abstract String getName();
    }
    class Solids extends Shapes implements Comparable{
        protected int len;
        protected int wid;
        protected int hig;
        protected double area;
        protected double volume;
        public Solids(int len, int wid, int hig){




        }
        public int compareTo(Object o){
            if (getVolume() >((Shapes)o).getVolume())
                return 1;
            else
                if (getVolume()<((Shapes)o).getVolume())
                    return -1;
                else
                    return 0;
        }
        public void setLen(int len){
            return;
        }
        public void setWid(int wid){
            return;
        }
        public void setHig(int hig){
            return;
        }
        public int getLen(){
            return len;
        }
        public int getWid(){
            return wid;
        }
        public int getHig(){
            return hig;
        }
        public String getName(){
            return "solid";
        }
        public double getArea(){
            return 0.0;
        }
        public double getVolume(){
            return 0.0;
        }
        public void print(){
            System.out.println("Solid of len"+len+" wid"+wid+" hig"+hig);
        }

    }

    class Cube extends Solids{
        protected int len;
        protected int wid;
        protected int hig;
        public Cube(int len, int wid, int hig){
            super(len,wid,hig);
            this.len=len;
            this.wid=wid;
            this.hig=hig;
        }
        public void calcArea(){
            area = 6*len*len;
        }
        public void calcVol(){
            volume = len*len*len;
        }
        public double getVolume(){
            return volume;
        }
        public double getArea(){
            return area;
        }
        public String getName(){
            return "Cube";
        }

    }
}

'... what can I do to fix the "AbstractShape.this cannot be referenced from a static context" error I am getting regarding my creation of cube1. ...'

This is because you are working within a method marked for static context.

The inner-class Cube requires an instance of its enclosing-class, AbstractShape; it's inferring this and cannot find the instance.

这是因为您正在标记为静态上下文的方法中工作。内部类Cube需要它的派生类AbstractShape的实例;它正在推断这一点，但找不到该实例。

There are two things you can do, and it is dependent upon your data requirements.

您可以做两件事，这取决于您的数据需求。

If you plan on instantiating your nested-classes from outside of your enclosing-class, then mark them as static.

如果您计划从封闭类外部实例化嵌套类，则将它们标记为静态。

static abstract class Shapes
static class Solids extends Shapes implements Comparable
static class Cube extends Solids

Otherwise, if Cube requires data specific to an instance of AbstractShape, just create an instance first.

否则，如果Cube需要特定于AbstractShape实例的数据，只需先创建一个实例。

AbstractShape abstractShape = new AbstractShape();
Cube cube1 = abstractShape.new Cube(4,4,4);
cube1.calcArea();
cube1.print();
Solids [] MySolids = new Solids[2];